Dark Side
by FantasyBeast14
Summary: What if Jack Frost had a dark side he struggled to keep at bay? What if one day, that side was set free? Follow the Guardians on their mission to rescue Jack from his evil half: Jokul Frosti. (Contains extreme, exaggerated portrayals of dissociative identity disorder. Should not be taken as an accurate idea of the reality of this illness.)
1. The Struggle Within

Prologue

 **The Struggle Within**

Jack tossed and turned as much as he could without falling out of his tree. He gripped and pulled at his hair, trying to keep the demon from escaping. It was a battle he had to fight on a daily basis for the last 250 years. For the most part he managed to keep him at bay, with the few occasional slip-ups. But even then he always managed to regain control quickly enough to prevent too much carnage. This time was different though. _He_ hasn't come this close to escaping the depths of his mind in decades. Jack was determined to maintain control but couldn't help but feel that he was fighting a losing battle. With his eyes clamped shut, he continued the struggle, not once noticing the pair of glowing yellow eyes watching him from the shadows.

Pitch

Pitch watched as the youngest Guardian fidgeted fitfully in his tree. The fear rolling off of his body was so dark, so pure, so delicious. Pitch could feel himself getting stronger by the minute! But he noticed something else radiating from the boy. An aura of evil and despair fought within the winter sprite, something that Pitch never expected from someone so pure of heart. He had, of course, heard the rumors; they were more than a century old. Rumors that he had perceived as nothing more than a mere myth once he had actually laid eyes on the Guardian of Fun. Now though, he thought that perhaps there was some truth to those stories after all. Stories of fear, destruction, and, above all else, death. A malicious, sadistic grin etched its way onto the Nightmare King's face. He knew what, or rather who, dear Jack was struggling with, and he was going to bring him out. His cruel laughter intermingled with Jack's frustrated cries as he spoke in barely a whisper:

"Worry not my friend; I shall set you free. The world will once again feel the wrath of Jokul Frosti."


	2. The Perversion of Jack Frost

"Where is he?!" said Bunnymund irritably. "He _would_ be late to his first meeting." Although he and Jack had been on better terms since the battle against Pitch, Bunnymund still wasn't entirely understanding of the younger sprite's mischievous ways. What the others saw as boyish charm, he interpreted as royal irresponsibility. "I'm sure he'll be here soon," Tooth said, her feathers ruffling as she flew around anxiously. "You know Jack. He prefers the scenic route; it's more fun." "Fun.." Bunny grumbled, rolling his eyes. Despite recent events, Bunnymund was not convinced that _fun_ was the proper way to act as a Guardian. Being a Guardian required certain levels of responsibility that he just didn't see Jack possessing. However, those opinions were not shared by the others, who had become quite fond of the boy, so Aster suffered in silence.

Aster was continuing to hop around North's workshop with impatience when he felt a sudden drop in the temperature – Jack had arrived, though it wasn't with his usual flair of icy style. Instead he looked worn out with dark bags under his eyes. He looked absolutely exhausted. Aster, who was about to lecture the winter sprite on his inexcusable tardiness, stopped in his tracks once he saw the look on his face, which was paler than usual. "Oi mate," Bunny started quietly, moving forward slowly. "Are you okay?" Jack looked up with a glazed look in his eyes and gave him a lazy smile. "Who, me?" He said, tired laughter in his voice. "I'm always okay, you old rabbit." Bunnymund looked back at the others; the looks on their faces clearly expressing their shared concern for their newest companion. North stepped forward and placed a hand on Jack's shoulder. "You do not look very well, my friend". Tooth began to hover around the boy, speaking as fast as her wings fluttered, asking if he needed anything and offering to bring him some cocoa. Jack just shrugged them off and back up towards the world globe. "Guys, I'm fine. Really."

Sandman was the only one who did not join in on the ministrations. It was not that he wasn't concerned for his friend's health. No, his attention was otherwise preoccupied by the dark shadow that was moving across the workshop. He looked towards his friends and knew that attempting to alert them, as usual, would be fruitless. Instead he approached the dark mass slowly, preparing for the possibility that he may need to defend himself.

"Really guys, there's nothing wrong with me," Jack said, almost irritably. "Baby Tooth, please," he said as the miniature Tooth Fairy buzzed around his head, tugging at his hair. He was exhausted and having everyone crowd around him was beginning to make him feel claustrophobic and a little bit nauseous. He hadn't slept at all in the last three days and wanted nothing more than to sit down and rest as the magic it took him to fly to the North Pole had all but drained him. He glanced around at the Guardians huddled around him, hoping Sandman could assist him in getting some much needed sleep and noticed that the golden Guardian of Dreams was not among them. "Hey," Jack said, interrupted the group's garbled words of concern. "Where's Sandy?"

Confused, the other three Guardians looked around for their missing friend but could not see him anywhere. "He was here a second ago," said Tooth, flying around the rafters of the workshop, searching for Sandman. "Sandy!" North called out. "Where are you my friend?" Bunnymund's nose twitched in his agitation, but he attempted calm the group by suggesting that Sandy had probably just dozed off somewhere. "You know the little bugger, spends more time asleep than he does awake, he does." But that did nothing to assuage his own feelings of concern, let alone that of the others. 'Come on little man,' Bunny thought. 'Where are ya?"

Sandman had followed the slithering shadows until he found himself all the way on the other side of the workshop. Realizing how vulnerable his isolation made him, Sandy backed away quickly and turned to race back to the Guardians. He was stopped in his tracks, however, when a glimmering rope of black nightmare sand wrapped around him tight and yanked him into the shadows.

Jack watched as his friends went searching for Sandy. Although he desperately wanted to find the only Guardian he had been on good terms with before their battle with Pitch, he simply did not have the energy to do so. Jack had practically collapsed into a nearby armchair as he felt like his legs may give out any second. He closed his eyes and listened to the sound of the others calling out to their missing companion. He thought he may finally drift off to sleep when he felt a sudden pang in his chest. His eyes flew wide open as he dropped from the chair onto his knees and began to clutch his chest desperately. His breathing became labored and it felt as though someone had reached inside him and had taken a firm grip on his heart, squeezing it until it couldn't possibly beat again.

Jack looked around him, unable to breathe, and saw the whirlpool of black sand moving quickly to surround him. He shut his eyes as tightly as he could and let out a guttural scream as he felt the change coming upon him.

Baby Tooth, like everyone else, had been buzzing around through every possible corner she could find in search of Sandman. Just when she considered giving up and flying back to Tooth, she felt an icy breeze ruffle her feathers and the familiar sense of apprehension, dread, and above all else, _fear_ course through her tiny body. They were feelings that she hoped to never feel again, for she knew there could be only one cause for them: Pitch was near. With a new sense of determination, Baby Tooth zipped off to find the Guardians.

As the miniature fairy flew off, a shadowy figure emerged from the walls, it's pale, glowing eyes following her as a dangerous smile grew upon its face. "Yes, little one," cooed Pitch. "Go and alert the others. We wouldn't want them to miss the show."

After thoroughly searching the workshop, North, Tooth, and Bunnymund all moved to reconvene in the globe room. "Hey…" started Tooth. "Have any of you seen Jack?" Concern was painted clearly on her face, her feathers ruffling. North and Bunny looked around, uneasy. First Sandman, now Jack? Something was going on, and it was far from good. Just then, Baby Tooth rushed over and began speaking frantically in her squeaky way, pointing towards the direction she came from. "Hold on, hold on. Slow down, Baby," Tooth said, trying to calm her favorite fairy. "What's wrong" But before Baby Tooth could answer, an animal like scream ripped through the air. It was a sound pain and loneliness. A sound of fear and hopelessness. A sound, they all knew, that came from Jack.

Without a second thought, the three remaining Guardians rushed towards their starting point, only to see that they were too late. When they had reached the meeting room, mere seconds later, they saw as a giant cloud of nightmare sand enveloped the winter spirit, drowning him in darkness.

"Jack!" Tooth yelled. She felt fear and anger bubble up inside her and flew head-on towards the mass of nightmare sand at full speed, the others following behind her, weapons ablaze. But it was no use; they just bounced right off. Still, the Guardians continued to attack at the wall of sand, giving all the got, praying to the Man in the Moon that their efforts would free their young friend.

An amused laugh reverberated through the air, causing the Guardians to halt their actions. Slowly they turned around and came face to face with Pitch Black as he materialized from the shadows, Sandy trapped within his grasp. "Don't bother," Pitch said, still laughing. "You won't be able to get to him before the transformation is complete." He paused for a moment. "Although, do go on trying, if you'd like. It's rather amusing," he mocked.

"Transformation," North questioned, stepping forward, swords still in hand. "Vhat transformation?" Pitch just laughed at the looks of confused trepidation on their faces.

"Oh, you'll see soon enough."

Jack felt like he was being ripped apart from the inside. He didn't know how much longer he could keep up the fight. He looked around, hoping to catch a glimpse of his friends, but all he saw was darkness. _'They don't care about you,'_ whispered a voice in the back of his mind. "No, stop it," Jack protested, covering his ears, as though that would block _his_ voice. _He_ just laughed. _'Come on Jackie,'_ he said. _It's been so long. Let me out to play.'_ Jack clenched his eyes shut and tried his hardest to bring back every happy memory he had. He tried to remember his sister, and Jamie. He tried to remember becoming a Guardian. But the nightmare sand surrounding him was blocking his efforts. For every happy memory he could think of, Pitch's sand brought back ten more bad ones. Three-hundred years of isolation. Three-hundred years of having kids walk through him. He remembered what it felt like when he drowned. He remembered the feeling of his lungs burning as they filled with water. He remembered the darkness, and to the darkness he finally succumbed.

Bunnymund growled when he saw the smug look on Pitch's face and wanted nothing more than to beat him with his boomerangs. But with a glance at Sandy, trapped in Pitch's black tendrils, he knew he'd be no match. The only two people who could fight Pitch one on one and win were currently incapacitated. There was nothing any of them could do, less they risk further harm to their friends. Instead, he attempted for information.

"Oi, what're you playing at?" he yelled up at the Nightmare King. "We may not be able to do much harm to ya, but you know just as well as I do that THAT," he emphasized, pointing back to Jack's sandy prison, "will not keep him trapped forever. And Jack is fully capable of kicking your arse back to the slimy whole you crawled out of." Pitch just laughed. "Oh I'm sure he could, were he in his proper state of mind." Sandman, who had long since abandoned his attempts at escape, looked up at his captor and towards his friends, a golden question mark appearing above his head.

"You haven't figured it out by now?" Pitch asked, "I would have thought it had been obvious. Especially for you North, with your wide range of knowledge." North grimaced at the backhanded compliment. "I don't suppose any of you have heard the stories that surround your young friend," Pitch teased, motioning towards the hurricane still surrounding Jack. The looks of confusion on their faces gave him the answer he needed. Pitch almost laughed; this would be much easier than he had previously predicted. Not even the Sandman seemed to understand where all this was going. The Guardians had no idea what was in store for them.

"Let me give you a hint," he said, grinning. "Ever heard of the name, _Jokul Frosti_?" North actually laughed despite the situation, the sound echoing through the air. "Frosti?" he said. "That is but a myth." Bunnymund too couldn't help but smile. "Yeah I've heard'a 'im," said Bunny. "Jack may be a pain, but he ain't no death dealing spirit of doom." The thought of Jack, skinny, loving Jack, wrecking chaos across the world was so ridiculous that even Tooth had to giggle a little. There was no way there could be any truth to those stories. Not after having actually met the boy in question.

Only Sandman seemed less confident in the mythos of Jokul Frosti. Being the eldest of the Guardians, he has seen many things. He remembered when winters became so harsh, they brought nothing but famine and death. He had always assumed that those dark days were the reason the Man in the Moon had turned Jack into a spirit. But what if Jack wasn't the solution? What if he was the cause?

Pitched watched as the three Guardians below him laughed at what seemed to them a ridiculous notion. A knowing smirk etched its way across his face as he addressed them once more. "Are you really so sure that the stories are so untrue? Tell me Guardians, have you really not noticed how agitated your little Jack has been lately?" Those words wiped the smiles off their faces, as they glanced at each other. None of them have really payed too close attention to Jack since the last they saw him. Something they quickly realized they may soon regret.

"Tsk, tsk Guardians." Pitch said, shaking his head. "What friends you are. How can you hope to protect the children of the world if you don't even notice the darkness stirring inside the mind of one of your very own?"

Suddenly, the nightmare sand that had surrounded Jack began to swirl around, bits of sand being thrown everywhere. The Guardians quickly turned around and stepped back, unsure of what to do. Pitch chuckled in grim delight. "And so it begins…"

The whirlpool of black sand died down and retreated towards pitch, exposing the figure of Jack, who was curled up on the ground, unmoving. "Jack!" yelled Tooth, who rushed to his side. "Jack, are you okay?" The Tooth Fairy knelt at his side and placed a delicate hand on his shoulder, her violet eyes filled with concern.

A low sound began to come from the boy, whose face was still concealed. Upon hearing it, the others, Pitch included, inched towards him. The sound grew in volume until it became recognizable as laughter. But it wasn't Jack's usual laughter, filled with childlike joy and wonder. No, this laugh was dark and full of malice. It left goosebumps on the Guardians' skin and was enough the make Baby Tooth hide behind her patron with a terrified squeal.

Jack began to move, pushing himself up to his feet, still laughing. The Guardians slowly backed away from him, unsure of what was happening. "Jack," Tooth said quietly, slowly reaching a hand out towards him. But the laughter continued.

Jack was on his feet now, his head bowed down so that they couldn't see his face. "Jackie isn't here anymore," he said between laughter. Tooth drew her hand back in fear. That voice was not the one she grew to know from the Guardian of Fun. Gone was the boyish charm that had encompassed every word. This voice was smooth and malevolent.

Jack looked up at the bewildered Guardians and revealed that his ice blue eyes were now dark, almost black. His pale skin was closer to that of Pitch's: ashy grey. "Crikey…" whispered Bunnymund, who stared in horror as the boy continued to change. His snow white hair and fingernails grew darker and darker until it rivaled the color of a moonless sky. Purplish bags appeared under his eyes, making his adolescent face appear gaunt and even manic. The frost that covered his staff turned grey, as if exposed to the smog of a big city, its wood decaying.

Even his clothes began to transform.

His signature frost covered hoodie darkened in color, it's sleeves lengthening and buckles appearing until it resembled a navy blue straight jacket, his pants turning blacker than onyx.

He no longer resembled the care-free spirit they and come to know.

The Guardians stared in shock as the transformation became complete, Pitch's satisfied laughter ringing in their ears.

Jack stepped towards them and took an exaggerated bow. He flashed a predatory smile in their direction and said, "Call me Jokul."


	3. Evil Unleashed

The Guardians stood in horror and shock as the creature who used to be Jack smiled at them. Jokul rose from his bow and began to walk around, twirling his staff as he looked at his surroundings. "Well, well North," he said, still grinning. "Quite the place you have here. A bit too jolly for my taste, but hey, to each their own, am I right?" He turned to look at the Guardians and said, "What? Frosbite caught your tongues?" Jokul laughed as the others just stood there staring at him. "It can't be...," North said softly, his eyebrows furrowing in frustration. "You are just a myth!" Jokul laughed again. "So are you, my fat friend! Don't you know by now that every myth must come from somewhere?"

"No!" Tooth cried. "Jack would never do the horrible things the stories say he's done. Jack would never-" "You're right," Jokul interrupted. " _Jack_ would never. But I would." Jokul grinned once more. The sight of his perfect teeth would normally be a comfort to Tooth, but coming from this new Jack, this _Jokul_ , it just made her shudder in fear.

Shaking his head, Bunny hopped forward. "I don't get it. You and Jack can't be the same person. It just ain't possible."

At this, Pitch slithered forward from his place in the shadows, where he had been growing bored of the exchange between the Guardians and his creation. "Ah but you see, they are not the same person at all," Pitch said as he made his way next to Jokul. He circled the boy, nightmare sand falling around them as he spoke: "They may occupy the same body, but they are by no means the same person."

Sandman brought his hands to his face and shook his head. Seeing this, Pitch felt a surge of joy as realization fell upon the golden dream-maker. "It's funny, the things loneliness can do to the mind," Pitch continued, feigning remorse. "And young Jack was so very lonely for so long, wasn't he, Jokul?" Jokul chuckled before responding: "Oh Jackie boy just couldn't take anymore. He cracked after the first couple of decades, and that's where I came in." Jokul moved past everyone and made his way towards the globe. "Jack and I do have one thing is common, you know. We both like to have fun." Jokul raised his staff and said, "Only difference is, I like to have the kind of fun Jack is too much of a coward to even consider."

The moment Jokul's staff touched the globe it began to rot. Black lines covered it, like diseased veins. The lights covering it flickered before giving out completely and the whole thing crumbled away, leaving nothing but a pile of dust in its wake. The Guardians gasped, stepping back from the scene. The magnitude of the problem had yet to fully process inside their minds. Despite everything that had happened so far, Jokul still had Jack's face, and that kept them from fully realizing the threat he was.

Pitch watched as Jokul stepped toward the rubble he had created. Jokul was exactly the partner in destruction he had hoped Jack would be. Together they would bring the world to its knees.

The Guardians could only watch in horror as Pitched walked towards Jokul with an out-stretched hand. "Come," he said to the boy. "Join me and together we can shroud the world in darkness." Jokul glanced at Pitch's hand and gave him an amused look. "Did you actually believe I would team up with you?" Jokul asked. Pitch's hand fell as confusion and rage set in. "You insolent child," he growled. "If it were not for me, you would still be stuck in the head of that happy little brat!" Jokul laughed. "You may have sped up the process but I would have gotten out on my own. Jackie was barely holding on as it was," he said before pushing past the Nightmare King. "Your nightmares are...cute, but relatively powerless in the big picture. You, like Jack, don't have the spine for real fun, and are therefore useless to me." Pitch stared at the boy, anger clear on his face, before charging toward him, hand out once again. Except this time, his hand was not out for a truce, but to grab the young spirit by the throat and lift him off the ground. "How dare you speak to me like that?" Pitch roared. "Do you even know who I am?"

Jokul eyes darkened. He raised a pale, ashen hand to circle Pitch's wrist. "Oh, I know who you are, Pitch Black." He said in a low, gravelly voice. "You're the Boogie Man. The Nightmare King. You're what goes bump in the night. But do you know what else you are? You're pathetic. You draw your power from the fears of little children because adults are too big of a challenge for you, because eventually they stop being afraid because eventually, everyone grows up to know that dreams aren't real and you? You can't do anything about it. You're weak. You're powerless. You're nothing." Pitch's eyes grew wide at Jokul's words, but Jokul didn't stop there. "You, however, don't seem to know who I am. I am the winter storm. I bring famine and death everywhere I go. I freeze the children who get lost playing in the woods, and cut off the limbs of those who stay out for too long. I trap people in their homes until they go insane with hunger and start killing each other. I kill crops and livestock until people are so starved, they begin eating their dead to survive. I'm a murderer, Mr. Black, and I don't think you quite understand just how much I enjoy what I do."

With those final words, Jokul tightened his grip on Pitch's wrist and ice began to creep up the Nightmare King's arm. Pitch cried out in fear and tried to pull away, but the boy's grip on him was too tight. The ice moved quickly, encompassing his body until only his face remained. No amount of struggling would free him and soon, his cries would fall silent.

Once Pitch was completely frozen over, Jokul swung his staff at his frozen wrist, freeing himself and allowing him to fall to the ground. He glanced at the frozen remains of the oh so feared Boogie Man and smirked in disgust. He gave the ice two taps before swinging at it with his staff, causing thing cracks to appear. Jokul kept swinging at it and swinging at it, hitting it hard enough that pieces began to crumble off, and he began to laugh. The same maniacal laugh the Guardians had heard before. He kept laughing as his blows broke Pitch apart piece by piece. First an arm, then his head, soon all that was left of Pitch Black was a pile of crushed ice.

The Guardians and watched as their greatest foe was murdered and torn apart in front of them. In all their days, not a single one of them had ever come across a creature as brutal as the one before them, but even as they watched the remains of Pitch Black begin to melt away, they could not look at the monster before them without thinking: _Jack._

Wiping the sweat of his forehead with his sleeve, Jokul looked up at the frightened Guardians with a wild look in his eyes. He let out yet another laugh. "I forgot you were there!" he exclaimed. Not a single Guardian had it in them to respond. "North, my old pal," Jokul said with a light-hearted tone, as if he had not just killed someone. "You may want to ask the Yetis to dispose of the mess. It won't be very pretty once everything thaws."

At that, North stepped forward. "You...You do not call me friend. You are monster!"

Jokul pouted playfully. "Are you saying we're not friends anymore?" he teased. "Well that's too bad. I was so looking forward to _playing_ with you."

Tears threatened to flow but Tooth forced them back. He looks so much like Jack, but he's not. He's not the same person. Glancing back at the pile of ice, she began to wonder if Jack was even in there anymore.

As Sandman stared at the young boy, he felt his heart grow heavy with sadness and regret. He knew that Manny had his reasons for keeping Jack alone for as long as he did, but he doubted even he could have foreseen the results of the boy's isolation. The pain and anger of being alone had torn Jack's mind in half, and now, they would all pay the price for it.

Bunnymund grew stoic as he listened to dark sprite taunting them. He wasn't Jack anymore, and Bunnymund knew that if they wanted any chance at stopping him, they would have to look past the face of the boy they once knew and be prepared to do what whatever it took to bring him down.

Jokul looked at them all and sighed. "Well, this has been fun, but it's time for me to go. It's been so long since I've been outside and I just can't wait to get out there and have fun." He began to fly towards the window, but before leaving, he turned to look back at the group below him and said, "I do hope you try and stop me." A feral grin spread across his lips. "I love a challenge." And just like that, he was gone.


	4. Comprehension

As Jokul flew out of sight, the Guardians slowly began to understand a few things:

1\. Jack had been in a lot more pain than they ever knew.

2\. Pitch saw what they never did and used that knowledge to his advantage.

3\. The stories were true; Jokul Frosti is very much real.

4\. Pitch is dead.

5\. Jack...Jokul murdered him.

The first fact was, as much as they would hate to admit, believable. The second is expected. But the reality that they all found so hard to grasp, despite having been witness to it themselves, is that Jack, their sweet, loving, Jack, was capable of such incomprehensibly twisted actions. They simply could not understand how two very different entities could somehow exist in the same mind. They could not understand how the Jack they knew could also be a murderer.

There wasn't a single one of them that didn't know the stories of Jokul Frosti. He was a legend far more frightening that even Pitch Black, because he had been right about one thing; everyone eventually comes to the realization that that their nightmares are nothing more than the figments of their imagination. Nightmares, while frightening, are only temporary as we escape from their grasp the moment we wake up. But what Jokul Frosti brings is something much worse than Pitch's nightmares.

He brings cold. Freezing cold with biting winds that will make you yearn for the fires of Hell just to keep warm.

He brings cannibalism. When the crops refuse to grow and the livestock cannot bear the cold, what is one to do but feed off the only meat available: each other?

He brings sickness, and worst of all, he brings death.

Jack Frost and Jokul Frosti. Two sides of the same coin, yet who would have guessed that they were one and the same?

Now, as the ice on the floor begins to melt and blood begins to flow, the Guardians look to each other and try to comprehend what they had just seen, and wonder how far they will have to go to bring an end to Jokul Frosti.


End file.
